These proposed studies will provide information on the control of renal and systemic hemodynamics during normal pregnancy and in pregnancies which are compromised by hypertension and proteinuria (pre-eclampsia) and underlying renal disease. It is intended, specifically, to investigate the factors which initiate the gestational rise in GFR, with particular reference to the renal vasodilator dopamine and the role of extra-cellular fluid volume expansion. Control of GFR in late pregnancy will also be investigated, with particular reference to tupulo-glomerular feedback control of GFR and to renal autoregulation. In addition, neurohumoral control of renal and systemic hemodynamics in mid- and late pregnancy will be evaluated with particular reference to the role of the sympathetic nervous system. The effect of dietary restriction of essential fatty acids, magnesium and calcicum in the pathogenesis of pre-eclampsia will also be investigated. Finally, studies will be performed to assess the effect of superimposition of pregnancy on underlying renal disease with regard to both the influence of pregnancy on the progression of the disease process and the effect of underlying renal disease on the renal response to gestation. The effects of repetitive pregnancy as a stimulus to prolonged nephron hyperfiltration will also be investigated, when superimposed on other hyperfiltration states. These studies will be performed using the "in-vivo" techniques of kidney micropuncture (under anesthesia) and in the awake, chronically catheterized rat.